Nostos asks the hero to survive the journey, then prove that he is still himself.
Odysseus' return is not a straight line toward an intact house. Each episode threatens one dimension of nostos: the desire to come back, memory of the self, the crew's trust, patience, recognition and political legitimacy.
That is why Ithaca is not merely a final harbor. The hero reaches it disguised, almost foreign to his own palace. He must read loyalties, recover his son, be recognized by Penelope and regain his place without confusing justice with simple revenge.
Nostos is therefore a moral theme as much as a geographical one. To return, in The Odyssey, means becoming someone again among one's own after being transformed by war and the sea. Return includes judgment, memory and renewed belonging.